package test2;

public class demo104 {
    /*
    * 二叉树的层序遍历
    *
    * 用队列存放
    *
    * */
/*
    class Solution {
        public List<List<Integer>> levelOrder(TreeNode root) {
            Queue<TreeNode> queue = new LinkedList<>();
            List<List<Integer>> res = new ArrayList<>();
            if (root != null) queue.add(root);
            while (!queue.isEmpty()) {
                List<Integer> tmp = new ArrayList<>();
                for(int i = queue.size(); i > 0; i--) {
                    TreeNode node = queue.poll();
                    tmp.add(node.val);
                    if (node.left != null) queue.add(node.left);
                    if (node.right != null) queue.add(node.right);
                }
                res.add(tmp);
            }
            return res;
        }
    }
*/

}
